I have data being persisted in Spring of employees and "personal development plans". Employee is the dominant class, so to speak. It looks like this:
#Entity(name = "employee")
#Table(name = "EMPLOYEE")
public class Employee {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "EMPLOYEE_ID")
private int id;
// etc...
}
Personal Development Plan looks like this:
#Entity(name = "pdp")
#Table(name = "PDP")
public class PersonalDevelopmentPlan implements Serializable {
#Id
#GeneratedValue
#Column(name = "PDP_ID")
private int id;
#ManyToOne(optional = false)
#JoinColumn(name = "EMPLOYEE_ID")
private Employee employee;
// etc..
}
In the database it is stored as a foreign key reference from PDP -> Employee.
I want to be able to load a PDP as it is in the database, with only employee id, but i always get the whole Employee object with all attributes. How do i do this?
I tried #ManyToOne(fetch = FetchType.Lazy) but this gives me the following error when fetching:
Type definition error: [simple type, class
org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor]; nested
exception is
com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No
serializer found for class
org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor and no
properties discovered to create BeanSerializer (to avoid exception,
disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference
chain:
java.util.ArrayList[0]->nl.kars.lms.model.pdp.PersonalDevelopmentPlan["employee"]->nl.kars.lms.model.Employee$HibernateProxy$AAwzPX4I["hibernateLazyInitializer"])
What am i doing wrong?
If you want only the ID, why not map it without the relationship ?
#Entity(name = "pdp")
#Table(name = "PDP")
public class PersonalDevelopmentPlan implements Serializable {
#Id
#GeneratedValue
#Column(name = "PDP_ID")
private int id;
#Column(name = "EMPLOYEE_ID")
private Long employeeId;
// etc..
}
It is actually how an ORM works... mapping table(relational side) to entities(object side). And mapping between entities is not done via ids but by entity references.
So either just persist the id (so remove strong relation) or use a projection query to just get back the employee Id.
You can create getter:
public Long getEmployeeId(){
return this.employee.getId();
}
Or you can change mapping to value private Long employeeId.
Related
I have tow classes, the "Article" which contains a #ManyToOne reference to a "SurchargeGroup" which specifies the surcharge for that article.
#Entity
#AllArgsConstructor
#NoArgsConstructor
#EqualsAndHashCode(doNotUseGetters = true)
#Audited
public final class Article {
#Id
#GeneratedValue(generator = "increment")
#GenericGenerator(name = "increment", strategy = "increment")
#Getter(onMethod_ = {#Key(PermissionKey.ARTICLE_ID_READ)})
#Setter(onMethod_ = {#Key(PermissionKey.ARTICLE_ID_WRITE)})
private int id;
#JoinColumn(nullable = false)
#ManyToOne
#Getter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_READ)})
#Setter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_WRITE)})
private SurchargeGroup surchargeGroup;
}
The other class "SurchargeGroup" contains a parent object reference which can inherit the surcharge to the "SurchargeGroup" if it isn't set the case that no surcharge is provided by any parent is not possible.
#Table
#Entity
#EqualsAndHashCode(doNotUseGetters = true)
#Audited
public class SurchargeGroup implements Serializable, Cloneable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column
#Getter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_ID_READ)})
#Setter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_ID_WRITE)})
private int id;
#Column
#Setter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_SURCHARGE_WRITE)})
private Double surcharge;
#Column
#Getter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_NAME_READ)})
#Setter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_NAME_WRITE)})
private String name;
#JoinColumn
#ManyToOne(fetch = FetchType.EAGER)
#Getter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_READ)})
#Setter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_WRITE)})
private SurchargeGroup parent;
public double getSurcharge() {
if (surcharge == null) {
return parent == null
? supplier == null
? Setting.SURCHARGE_DEFAULT.getDoubleValue()
: supplier.getDefaultSurcharge()
: parent.getSurcharge();
} else return surcharge;
}
#JoinColumn
#ManyToOne
#Getter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_READ)})
#Setter(onMethod_ = {#Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_WRITE)})
private Supplier supplier;
}
My problem is now that if I call the "getSurcharge()" method I get this exception which I cannot explain to myself because I marked the surcharge group to fetch eager
Exception in thread "AWT-EventQueue-0" org.hibernate.LazyInitializationException: could not initialize proxy [kernbeisser.DBEntities.SurchargeGroup#1046] - the owning Session was closed
at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:172)
at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:309)
at org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor.intercept(ByteBuddyInterceptor.java:45)
at org.hibernate.proxy.ProxyConfiguration$InterceptorDispatcher.intercept(ProxyConfiguration.java:95)
at kernbeisser.DBEntities.SurchargeGroup$HibernateProxy$cdTAuBkS.getSurcharge(Unknown Source)
I asked myself if this could get caused by the #Audited annotation? Any ideas? Thanks a lot!
Note: the #Key annotations have no effect to this scenario.
Here is what the debugger shows (Sorry for the German toString() functions):
Hibernate needs to stop eagerly fetching associations at some point, otherwise it would need to join an infinite number of times the SurchargeGroup entity (since it references itself).
The depth these fetches can be controlled application wide using the hibernate.max_fetch_depth property.
The source of the error was the AuditReader it doesn't fetch all eager properties even if they are annotated as Fetch.EAGER
It looks like the AuditReader only fetches one level of eager relations:
Article -> SurchargeGroup -> SurchargeGroup -> ...
(fetched) (fetched) (not fetched)
I'm mapping a relationship that does not use the entity's primary key. Using "referencedColumnName" with a column different than the primary key causes hibernate to eagerly fetch the association, by issuing an extra select, even when it's tagged with FetchType.LAZY.
My goal is to make it behave like a regular mapping, meaning it wouldn't issue an extra query every time I need to query the main entity.
I have already tried using #LazyToOne(LazyToOneOption.NO_PROXY), which sorts out the problem, but it does not operate well with Jackson's (JSON parsing library) module "jackson-datatype-hibernate5", which skips hibernate lazy proxies when serializing the results.
Here is a scenario almost like the one I have that causes the problem:
Entities:
#Entity(name = "Book")
#Table(name = "book")
public class Book
implements Serializable {
#Id
#GeneratedValue
private Long id;
private String title;
private String author;
#NaturalId
private String isbn;
//Getters and setters omitted for brevity
}
#Entity(name = "Publication")
#Table(name = "publication")
public class Publication {
#Id
#GeneratedValue
private Long id;
private String publisher;
#ManyToOne(fetch = FetchType.LAZY)
#JoinColumn(
name = "isbn",
referencedColumnName = "isbn"
)
private Book book;
#Column(
name = "price_in_cents",
nullable = false
)
private Integer priceCents;
private String currency;
//Getters and setters omitted for brevity
}
Repository (Spring-Data, but you could try directly with the EntityManager):
#Repository
public interface PublicationRepository extends JpaReadRepository <Publication, Long>
{
#Query ("SELECT d FROM Publication d WHERE d.publisher = ?1 ")
Optional <Publication> findByPublisher (String isbn);
}
Thanks
The only way to achieve what you are looking for is by moving the annotatation #Id to the isbn property.
You can leave the #GeneratedValue on the autoincrement property.
Notes:
1 - Make sure that your equals/hc are following the OID(Object ID) on your domain case the "NaturalId" ISBN.
2 - It will be good to ensure if possible on DB level that your natural ID has unique contraint on it.
I have entity called Shop and different types of shops (sport, clothes, tech...). That list of types will probably be predefined. One shop can have multiple types. What is the best way to represent that?
I created two entities Shop and Type.
#Entity
#Table(name = "store")
public class Store {
#GeneratedValue(strategy = GenerationType.AUTO)
#Id
private Long id;
...
}
#Entity
#Table(name = "type")
public class Type {
#GeneratedValue(strategy = GenerationType.AUTO)
#Id
private Long id;
private String name; //sport, clothes, tech...
}
What type of relationship between these two entities should I use?
Given that you said Type is probably predefined, it seems more reasonable to model it as enum, and making use of ElementCollection
(I have to admit that I haven't tried to use them both in combination, I believe it should work though :P )
public enum Type {
SPORT, CLOTHES, TECH
}
public class Shop {
#Id
private Long id;
#ElementCollection
#CollectionTable(
name="SHOP_TYPE",
joinColumns=#JoinColumn(name="SHOP_ID")
)
#Column(name="TYPE")
// mapping for enum by usertype or other way, depending on JPA version you are using
private List<Type> types;
}
Of course, you can model SHOP_TYPE as an entity (e.g. ShopType) if you want more complicated operations on it, but what described above looks to me a more reasonable domain model.
Even you do not want the Type to be predefined (i.e. you can create whatever type in your application), it is still more reasonable to model it as a ManyToMany relationship:
public class Type {
#Id
#Column(name="TYPE_ID")
private Long id
#Column(name="TYPE_NAME")
private String name;
}
public class Shop {
#Id
#Column(name="SHOP_ID")
private Long id;
#ManyToMany
#JoinTable(
name="SHOP_TYPE",
joinColumns=#JoinColumn(name="SHOP_ID"),
inverseJoinColumns=#JoinColumn(name="TYPE_ID"))
private List<Type> types;
}
Just one thing to note: It does not look right to have a Type entity which contains a String as type name, and refer to Shop (as some of the answer suggested). Type should be an entity of itself, and, for example, different shops having CLOTHES type should refer to same CLOTHES entity (unless you view types as some kind of arbitrary tag)
The Store and Type many to many relationship is linked with a third / join table named STORE_TYPE_MAPS.
Store Entity:
#Entity
#Table(name = "store")
public class Store {
#GeneratedValue(strategy = GenerationType.AUTO)
#Id
private Long id;
#ManyToMany(fetch = FetchType.LAZY, targetEntity=Type.class)
#JoinTable(name="STORE_TYPE_MAPS",
joinColumns=#JoinColumn(name="STORE_ID"),
inverseJoinColumns=#JoinColumn(name="TYPE_ID")
private Set<Type> types;
//... getter-setter
}
If Type is an Entity then make it ManyToMany
#ManyToMany
#JoinTable(name="Store_Type")
private List<Type> types;
also it can be an enum
I rather prefer to create a new entity called ShopType, the ManyToMany relationship will be created as explained below.
This new Entity allows you to have extra columns in the join table, "ShopType", (which can't be done with a simple #ManyToMany). For example, you can add this information: "the number of articles of each type in each shop".
The code is as follows:
public class Shop {
#Id
#Column(name="SHOP_ID")
private Long id;
#OneToMany(mappedBy = "shop", cascade = CascadeType.ALL)
private List<JoinAchatType> joinShopType = new ArrayList();
}
public class ShopType {
#ManyToOne
#JoinColumn(name = "SHOP_ID")
private Shop shop;
#ManyToOne
#JoinColumn(name = "TYPE_ID")
private Type type;
private int numberArticle;
}
public class Type {
#Id
#Column(name="TYPE_ID")
private Long id;
#OneToMany(mappedBy = "type", cascade = CascadeType.ALL)
private List<JoinAchatType> joinShopType = new ArrayList();
}
For more information check these links:
Mapping many-to-many association table with extra column(s)
.
The best way to use the #ManyToMany annotation with JPA and Hibernate.
I have a two objects with simple #OneToMany relationship which looks as follows:
parent:
#Entity
public class ParentAccount {
#Id
#GeneratedValue
private long id;
private String name;
#OneToMany(fetch = FetchType.EAGER, mappedBy = "parentAccount")
private Set<LinkedAccount> linkedAccounts;
}
child:
#Entity
public class LinkedAccount {
#Id
#GeneratedValue
private long id;
#ManyToOne(optional = false)
private ParentAccount parentAccount;
private String name;
// empty constructor for JPA
public LinkedAccount() {
}
}
I ma using Spring CrudRepository to operate with these entities. However, when calling ParentAccount parent = parentAccountRepository.findOne(id);, some kind of infinite loop starts happening and hibernate spams this all over the console:
Hibernate: select linkedacco0_.parent_account_id as parent_a6_1_0_, linkedacco0_.id as id1_0_0_, linkedacco0_.id as id1_0_1_, linkedacco0_.aws_id as aws_id2_0_1_, linkedacco0_.key_id as key_id3_0_1_, linkedacco0_.name as name4_0_1_, linkedacco0_.parent_account_id as parent_a6_0_1_, linkedacco0_.secret_key as secret_k5_0_1_ from linked_account linkedacco0_ where linkedacco0_.parent_account_id=?
I tried changed the fetch type to LAZY but then I get this error:
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.berrycloud.scheduler.model.ParentAccount.linkedAccounts, could not initialize proxy - no Session
(It seems that it is trying to do the lazy load outside of the transactional context).
This is my CRUD repository:
#Repository
public interface ParentAccountRepository extends CrudRepository<ParentAccount, Long> {
}
Could someone tell me how to resolve this issue? I would prefer the solution with EAGER fetch. Thank you for any tips
EDIT: here is the schema I am using
CREATE TABLE parent_account (
id BIGINT auto_increment,
name VARCHAR(80) null,
PRIMARY KEY (`id`)
);
CREATE TABLE linked_account (
id BIGINT auto_increment,
parent_account_id BIGINT,
name VARCHAR(80) null,
FOREIGN KEY (`parent_account_id`) REFERENCES `parent_account` (`id`),
PRIMARY KEY (`id`)
);
As the first answer suggests:
Do not use Lombok's #Data annotation on #Entity classes.
Reason: #Data generates hashcode(), equals() and toString() methods that use the generated getters. Using the getter means of course fetching new data even if the property was marked with FetchType=LAZY.
Somewhere along the way hibernate tries to log the data with toString() and it crashes.
Problem solved. I was using a custom #toString method in the LinkedAccount which was referencing the ParentAccount. I had no idea that this could cause any problem and therefor I did not include the toString in my question.
Apparently, this was causing an infinite loop of lazy loading and removing this reference fixed the problem.
As user1819111 told, #Data from Lombok is not compatible with #Entity and FetchType=LAZY. I had used Lombok.Data (#Data) and I was getting this error.
As I don't want do create all get/set, I just put the Lombok #Setter and #Getter in your class and all will work fine.
#Setter
#Getter
#Entity
#Table(name = "file")
#SequenceGenerator(name = "File_Sequence", allocationSize=1, sequenceName = "file_id_seq")
public class MyClass{
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "File_Sequence")
#Column(name = "id")
private Long id;
#Column(name = "name")
private String name;
#OneToMany(mappedBy = "file", cascade = CascadeType.DETACH, fetch = FetchType.LAZY)
private Set<Base2FileDetail> details = new HashSet<>();
}
Something like this does not work?
#Entity
public class Account {
#Id
#GeneratedValue
private long id;
private String name;
#ManyToOne(cascade={CascadeType.ALL})
#JoinColumn(name="manager_id")
private Account manager;
#OneToMany((fetch = FetchType.EAGER, mappedBy="manager")
private Set<Account> linkedAccounts = new HashSet<Account>();
}
I recently had this issue due to a poorly defined Jackson2HttpMessageConverter.
I had done something like the following.
#Bean
RestTemplate restTemplate(#Qualifier("halJacksonHttpMessageConverter")
TypeConstrainedMappingJackson2HttpMessageConverter halConverter) {
final RestTemplate template = new RestTemplateBuilder().build();
halConverter.setSupportedMediaTypes(List.of(/* some media types */));
final List<HttpMessageConverter<?>> converters = template.getMessageConverters();
converters.add(halConverter);
template.setMessageConverters(converters);
return template;
}
This caused a problem because the media types did not include all the defaults. Changing it to the following fixed the issue for me.
halConverter.setSupportedMediaTypes(
new ImmutableList.Builder<MediaType>()
.addAll(halConverter.getSupportedMediaTypes())
.add(/* my custom media type */)
.build()
);
This simple way worked for me. Just use JsonIgnoreProperties .
#JsonIgnoreProperties(value = {"linkedAccounts"})
#ManyToOne(cascade = { CascadeType.PERSIST})
#JoinColumn(name = "abc", referencedColumnName = "abc")
private ParentAccount parentAccount;
This way worked for me without removing #ToSring annotation:
#Entity
#Getter
#Setter
#ToString
#RequiredArgsConstructor
#AllArgsConstructor
#Table(name = "parent_accounts")
public class ParentAccount {
#JsonIgnoreProperties({"parentAccount"})
#OneToMany(mappedBy = "parentAccount",
cascade = CascadeType.ALL,
orphanRemoval = true)
private List<LinkedAccount> linkedAcounts;
// ...
}
#Entity
#Getter
#Setter
#ToString
#RequiredArgsConstructor
#AllArgsConstructor
#Table(name = "linked_accounts")
public class LinkedAccount {
#JsonIgnoreProperties("linkedAcounts")
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "parentAccount_id")
private ParentAccount parentAccount;
// ...
}
PS: In #JsonIgnoreProperties You can also ignore more than one field for preventing infinite loop
I am working on a web app and I am using JSF and JPA(EclipseLink). I have the tables story and story_translate, which are mapped as follows:
#Entity
#Table(name = "story")
public class Story{
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private Integer id;
private String title;
private String description;
#OneToMany(mappedBy = "story", cascade=CascadeType.ALL)
private List<StoryTranslate> translateList;
//getters and setters
}
#Entity
#Table(name = "story_translate")
public class StoryTranslate{
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private Integer id;
#Column(name="STORY_ID")
private Integer storyId;
#ManyToOne
#JoinColumn(name="story_id", referencedColumnName="id", updatable=false, insertable=false)
private Story story;
//some other fields, getters and setters
}
In a ManagedBean I am doing the following:
StoryTranslate translate = new StoryTranslate(null, sessionController.getEntity().getId(), getAuthUser().getId(), language,
title, description, new Date(), false);
EntityTransaction transaction = TransactionSingleton.getActiveInstance();
Story story = storyService.read(sessionController.getEntity().getId());
if (story != null){
if (story.getTranslateList() == null){
story.setTranslateList(new ArrayList<StoryTranslate>());
}
story.getTranslateList().add(translate);
translate.setStory(story);
}
transaction.commit();
When I try to create a new StoryTranslate, I get a DatabaseException, saying the story_id cannot be null.
I have managed relationships before, but I have never seen this error.
Where is the problem?
EDIT: I am sorry, but I have forgotten about another part of the mapping(must be the lack of sleep).
The problem is that your declare the storyId property in the StoryTranslate class for the STORY_ID column but when adding a new StoryTranslate , you do not set any value to its storyId property and I believe STORY_ID column has a NOT NULL constraint and that why you get the exception saying that story_id cannot be null.
The problem should be fixed once you set the storyId property of the StoryTranslate instance before committing the transaction .
But it is strange that you map the STORY_ID column to two different properties ( storyId and story) of the StoryTranslate class . Actually you do not need to declare storyId property as this value can be retrieved from the story instance . I suggest you change the mapping of StoryTranslate to the following and your code should work fine without any changes.
#Entity
#Table(name = "story_translate")
public class StoryTranslate{
#Id
#GeneratedValue(strategy = GenerationType.SEQUENCE)
private Integer id;
#ManyToOne
#JoinColumn(name="story_id")
private Story story;
//some other fields, getters and setters
}